In this dissertation, we investigate the n=0 Geodesic Acoustic Modes (GAM) in the framework of both magneto-hydrodynamics and kinetics. In MHD, the purpose is to understand the numerical results out of the CASTOR code (1). Effects of energetic particle are ignored. The leading perturbation is the density perturbation, which leads to a local GAM. The coupling of density perturbation to the magnetic perturbation, which is treated to be smaller, leads to global a GAM. We recover the numerical results from the CASTOR code and obtain and analytical solution to the radial eigen-mode equation though asymptotic matching. To understand recent experimental results on DIII-D (2) a kinetic theory is constructed in which magnetic perturbations are neglected and energetic ions are treated on the same footing as the thermal species based on drift kinetics. Not only do the energetic particles destabilize the local GAM induced by thermal species, but they are also crucial to establish the global GAM due to their large orbit shifts. Polarization of thermal ions is included. A mechanism for fast GAM excitation through NBI is proposed, based on our local kinetic GAM theory when there exists a loss boundary in pitch angle. / text

Revision of the author's Thesis (Ph. D.)--University of Stellenbosch, 1988. / Opp. t.p.: "Münchener Universitätsschriften. Philosophische Fakultät Altertumskunde und Kulturwissenschaften." Includes bibliographical references.

Red deer (Cervus elaphus) is one of at least 31 herbivorous exotic mammals existing in New Zealand. All of these species have the potential to affect environmentral and production values. Reducing their impacts on their values, strengthening effective managements are important issues to a variety of agencies within New Zealand including the Department of Conservation (DOC), Ministry of Agriculture and Forestry (MAF), local and regional governments. This research studied animal movement pattern and habitat use of 2 GPScollared red deer in the Canterbury high country and found (1) deer movement was affected by climatic variables such as rainfall and temperature, which had positive or negative effect on it, and had seasonal variation; (2) deer had dominant landcover use categories, depending on climate, season, and individual characteristics (3) deer had different movement patterns in terms of hourly distances. The purpose of the study is to draw accurate inferences from spatially explicit data for biosecurity managers and policy-makers through: (1) using global positioning system (GPS) as a tool to elucidate the application of GPS on red deer in wildlife management; (2) Animal Movement Analysis Arc View® 3.2 Extension under Arc View® Geographic Information System (GIS); (3) Animal movement analysis which used Generalized Additive Models (GAMs) to show how the movement of red deer was affected by different periods of time, seasons months and climatic variables (for example, rainfall and temperature).

The influence of ‘credit crunch’ on Small and Medium sized Enterprises (SMEs) has been of concern to the government, regulators, banks, the enterprises and the public. Using a large dataset of UK SMEs’ records covering the early period of the ‘credit crunch’, the influence of the ‘credit crunch’ on SMEs have been studied. It uses cross-sectional method, panel data models and GAM to provide a detailed examination of SMEs performance. Both newly established and matured SMEs, segmented by age, are considered separately. The data contains 79 variables which covered obligors’ general condition, financial information, directors’ portfolio and other relevant credit histories. The ‘credit crunch’ is a typical ‘black swan’ phenomenon. As such there is a need to examine whether the stepwise logistic model, the industries prime modelling tool, could deal with the sudden change in SMEs credit risk. Whilst it may be capable of modelling the situation alternatives models may be more appropriate. It provides a benchmark for comparison to other models and shows how well the industry’s standard model performs. Given cross-sectional models only provide aggregative level single time period analysis, panel models are used to study SMEs performance through the crisis period. To overcome the pro-cyclic feature of logistic model, macroeconomic variables were added to panel data model. This allows examination of how economic conditions influence SMEs during ‘credit crunch’. The use of panel data model leads to a discussion of fixed and random effects estimation and the use of explanatory macroeconomic variables. The panel data model provides a detailed analyse of SMEs’ behaviour during the crisis period. Under parametric models, especially logistic regression, data is usually transformed to allow for the non-linear correlation between independent variable and dependent variable. However, this brings difficulty in understanding influence of each independent variable’s marginal effects. Another way of dealing with this is to add non-parametric effects. In this study, Generalized Additive Models (GAM) allows for non-parametric effects. A natural extension of logistic regression is a GAM model with logistic link function. In order to use the data in their original state an alternative method of processing missing values is proposed, which avoids data transformation, such as the use of weights of evidence (WoE). GAM with original data could derive a direct marginal trend and plot how explanatory variables influence SMEs’ ‘bad’ rate. Significant non-parametric effects are found for both ‘start-ups’ and ‘non-start-ups’. Using GAM models results in higher prediction accuracy and improves model transparency by deriving explanatory variables’ marginal effects.

Orientador: Rogerio Caetano Costa / Resumo: Farfantepenaeus brasiliensis and F. paulensis are commonly exploited in the north of São Paulo because of their commercial value. The evaluation of the state of conservation of these species is difficult to perform, since both are landed as pink shrimp, which generates scarce data and makes impossible reliable ecological analyzes. Thus, this study evaluated through Generalized Additive Models (GAMs) the juvenile catches per unit of effort in abundance (CPUEn) and biomass (CPUEw) of these species and their relationships with environmental factors in the Ubatuba Bay in an interval of 22 years (1995 to 2017). The F. paulensis CPUEn model showed high catches recorded in months of the first semester and a strong influence of years under such monthly patterns. Also, there was a greater abundance in increased pluviosity, Phi < 4.5 and in moderate and strong La Niña and El Niño. CPUEw varied through the years, with increase in biomass from 2005, and in rainy periods. The F. brasiliensis CPUEn model presented high abundance from January to May, specially from 2010. Higher catches were also recorded in El Niño events, as well in Phi < 4.5 and OM < 15. CPUEw was mainly influenced by Phi. Although juveniles of both species were present in the bay during the months prior to the closure season it seems that there is maintenance of populations. / Mestre

Red deer (Cervus elaphus) is one of at least 31 herbivorous exotic mammals existing in New Zealand. All of these species have the potential to affect environmentral and production values. Reducing their impacts on their values, strengthening effective managements are important issues to a variety of agencies within New Zealand including the Department of Conservation (DOC), Ministry of Agriculture and Forestry (MAF), local and regional governments. This research studied animal movement pattern and habitat use of 2 GPScollared red deer in the Canterbury high country and found (1) deer movement was affected by climatic variables such as rainfall and temperature, which had positive or negative effect on it, and had seasonal variation; (2) deer had dominant landcover use categories, depending on climate, season, and individual characteristics (3) deer had different movement patterns in terms of hourly distances. The purpose of the study is to draw accurate inferences from spatially explicit data for biosecurity managers and policy-makers through: (1) using global positioning system (GPS) as a tool to elucidate the application of GPS on red deer in wildlife management; (2) Animal Movement Analysis Arc View® 3.2 Extension under Arc View® Geographic Information System (GIS); (3) Animal movement analysis which used Generalized Additive Models (GAMs) to show how the movement of red deer was affected by different periods of time, seasons months and climatic variables (for example, rainfall and temperature).

In diesem Beitrag wird eine Regressionsanalyse vorgestellt, die die Einflüsse auf die Entscheidung verheirateter deutscher Frauen untersucht, eine Erwerbstätigkeit aufzunehmen. Um Differenzen im Verhalten von ost- und westdeutschen Frauen zu ermitteln, erfolgte die Untersuchung getrennt in zwei Datensätzen. Zur Vermeidung von Annahmen über die Art des Zusammenhanges wurde das Generalisierte Additive Modell (GAM) gewählt, ein semiparametrisches Regressionsmodell. Diese Modellform, die nichtparametrische und parametrische Regressionsmethoden in sich vereint, hat bisher wenig Verbreitung in der Praxis gefunden. Dies lag vor allem am Schätz verfahren, dem Backfitting. Seit etwa einem Jahr gibt es neue Ansätze, in dieser Modellform zu schätzen. Die analytischen Eigenschaften des neuen Schätzers lassen sich leichter bestimmen. Mit dieser Schätzung konnten Unterschiede zwischen Ost und West genau herausgearbeitet werden und die funktionalen Zusammenhänge zwischen Einflußvariablen und Antwortvariable untersucht werden. Die Analyse brachte deutliche Unterschiede im Erwerbsverhalten zwischen der Frauen beider Landesteile zum Vorschein. / This paper will focus on the regression analysis of labor supply decisions of married German women. In order to determine differences East and West German women were compared seperately. To avoid assumptions about the functional type of correlation the Generalized Additive Model, a semiparametric regression model, was chosen. So far, this pattern consisting of nonparametric and parametric methods has not found acceptance in practical application. Reason for that is the backfitting-estimator. One year ago new ideas for the estimation by GAM were found. The analytical features of the new estimator are easier to determine. Using this method differences between East and West were discovered in detail and functional correlations between endogenous and exogenous variables were investigated. This analysis unveiled significant differences of labor supply behavior among East and West Germany.

Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-08-07T21:23:32Z No. of bitstreams: 1 CiroJFS_DISSERT.pdf: 1024163 bytes, checksum: a88ae5c8cfa098bda9110c757cf1215e (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-08-17T22:38:36Z (GMT) No. of bitstreams: 1 CiroJFS_DISSERT.pdf: 1024163 bytes, checksum: a88ae5c8cfa098bda9110c757cf1215e (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-08-17T22:38:45Z (GMT) No. of bitstreams: 1 CiroJFS_DISSERT.pdf: 1024163 bytes, checksum: a88ae5c8cfa098bda9110c757cf1215e (MD5) / Made available in DSpace on 2017-08-17T22:40:42Z (GMT). No. of bitstreams: 1 CiroJFS_DISSERT.pdf: 1024163 bytes, checksum: a88ae5c8cfa098bda9110c757cf1215e (MD5) Previous issue date: 2015-09-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of the study was to evaluate the effect of variables that influence the capture, in terms of biomass,of Anomalocardia brasiliana from the artisanal fisheries in Rio Grande do Norte estuary. For this accompaniments of production were conducted during the years 2007-2011. The variables tested in the preparation of the production model were as follows: year, month and salinity. It was observed that only these three variables were responsible for explanation of 22% of the total variance that influences the gross production of seafood. This initial result corroborates for creation and implementation of management plans for the shellfish fishery in the area / O objetivo do estudo foi avaliar o efeito das variáveis que influenciam a captura, em termos de biomassa, de Anomalocardia brasiliana provenientes da pescaria artesanal em um estuário do Rio Grande do Norte. Para isso foram realizados acompanhamentos de produção durante os anos de 2007 a 2011. As variáveis testadas na elaboração do modelo de produção foram: mês, ano e salinidade. Observou-se que apenas estas três variáveis foram responsáveis pela explicação de 22% da variação total que influencia na produção bruta do marisco. Esse resultado inicial corrobora para criação e implementação de planos de manejo para a pescaria do marisco na região / 2017-08-07

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-01-06T14:31:54Z No. of bitstreams: 1 danielaferrodegodoy.pdf: 2931952 bytes, checksum: 08ac03607124e73f9ec9318d1bbc4e9a (MD5) / Approved for entry into archive by Diamantino Mayra (mayra.diamantino@ufjf.edu.br) on 2017-01-31T11:25:03Z (GMT) No. of bitstreams: 1 danielaferrodegodoy.pdf: 2931952 bytes, checksum: 08ac03607124e73f9ec9318d1bbc4e9a (MD5) / Made available in DSpace on 2017-01-31T11:25:03Z (GMT). No. of bitstreams: 1 danielaferrodegodoy.pdf: 2931952 bytes, checksum: 08ac03607124e73f9ec9318d1bbc4e9a (MD5) Previous issue date: 2016-07-12 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A modelagem pode ser utilizada para determinar a distribuição de uma determinada espécie em uma área. Deste modo, pode auxiliar na conservação de espécies ameaçadas. Neste estudo, modelos foram utilizados para avaliar a influência do habitat, do tipo de presas capturadas por pescadores artesanais e do Valo Grande sobre a presença do boto-cinza na região do Complexo Estuarino Lagunar de Cananéia. Os dados foram coletados entre janeiro de 2012 a novembro de 2014, durante três 3 saídas de campo por estação do ano. Estas saídas de campo foram realizadas em quatro setores pré-definidos, que foram percorridos em transecções lineares. O setor II foi o de maior ocorrência de botos, provavelmente pela proximidade com o oceano adjacente. A distribuição entre os setores foi mais homogênea nas estações mais frias, onde os valores das variáveis ambientais são mais estáveis. Os maiores agrupamentos de animais também foram encontrados no inverno. Os botos foram avistados em diversos valores das variáveis ambientais analisadas. No entanto, as maiores ocorrências foram registradas em águas mais turvas; profundidades maiores que 10 metros; salinidade acima de 10 ppm; e águas mais frias e nas marés de sizígias. A presença do cerco-fixo no estuário também influenciou positivamente a ocorrência dos botos, que utilizam essa armadilha de pesca como barreira, minimizando a fuga das suas presas. A tainha foi a categoria de peixe que teve a maior associação com a presença dos botos, seguida pela guaivira e prejereba. Já o parati e o camarão estuarino apresentaram uma influência negativa com a presença do boto. O modelo preditivo do Valo Grande mostrou que a descarga de água doce influencia de maneira negativa na presença dos botos. Pelo exposto, fica claro que os botos-cinza apresentaram uma distribuição heterogênea dentro do estuário estudado e as áreas de maior concentração merecem maior atenção na elaboração de estratégias de conservação. / Niche modelling can be used to determine the distribution of a particular species in an enviromental space (ecological niche). It may be important to help to preserve endangered species. Therefore, in this study, niche modelling was used to evaluate the influence of: the habitat; the artisanal fishermen‟s catch species; and the Valo Grande on the presence of the Guiana dolphins (Sotalia guianensis) in the Estuarine Lagunar Complex of Cananéia, Brazil. The data were collected in three fieldworks per season, from January 2012 to November 2014. The fieldworks took place in four predefinied sectors. These sectors were sampled using a line-transect method. The presence of the Guiana dolphin was observed mostly on sector II. Probably because of the proximity to the adjacent ocean. The distribution among sectors was more homogeneous in the short cool season, when the environmental variables are more stable. The larger dolphin clusters were found during the winter. Guiana dolphins were sighted in a great diversity of environmental conditions. Nonetheless, the highest occurrences were recorded in cooler and turbid waters; depths greater than 10 meters; salinity above 10 ppm; and during spring tides (technically known in Portuguese as 'maré de sizígia'). Furthermore, the presence of an artisanal fish trap, known locally as cerco-fixo, has positively influenced the occurrence of Guiana dolphins in the estuary. The dolphins use cerco-fixo fish traps to corner shoals and reduce the escape routes of their prey. The mullet (Mugil brasiliensis) was the fish species which had the highest positive correlation with the presence of dolphins, followed by the leatherjacket (Oligoplites saurus) and the tripletail (Lobotes surinamensis). On the other hand, the white mullet (Mugil curema) and the whiteleg shrimp (Litopenaeus vannamei) had a negative correlation with the presence of the Guiana dolphin. The data collected on the Valo Grande Channel showed that freshwater discharges decrease the presence of Guiana dolphins. We can conclude that the Guiana dolphins have an heterogeneous distribution within the studied estuary. Therefore, the areas of greatest ocurrence deserve greater attention in the development of preservation strategies.

Devido à sua importância em turbulência causada por ondas de deriva e à aplicação com propósitos em diagnósticos de plasma, a investigação de fluxos zonais (ZF) e modos acústicos geodésicos (GAM) tem atraído bastante atenção na literatura em física de plasmas. Nesta tese, primeiramente consideramos efeitos de equilíbrio com rotação poloidal e toroidal nestes modos, posteriormente investigamos efeitos diamagnéticos em GAM a partir de um modelo de dois fluido, no qual incluímos viscosidade paralela de íons e, na parte final, consideramos amortecimento de Landau e efeitos diamagnéticos simultaneamente no estudo de GAM, porém, a partir do modelo girocinético. Efeitos diamagnéticos são causados por termos que envolvem gradientes de densidade e de temperatura provenientes da função Maxwelliana de equilíbrio. O acoplamento entre os harmônicos poloidais, $m = \\pm1$, e as derivadas radiais de quantidades macroscópicas do plasma é responsável pelo aumento no valor da frequência no GAM de alta frequência e pela instabilidade no GAM de baixa frequência. Este tipo de instabilidade, que é proporcional à frequência diamagnética de elétrons e à razão entre os gradientes de temperatura e de densidade, é mais propenso a ocorrer em posições radiais em que o fator segurança é alto. Modos geodésicos são fracamente amortecidos devido a um mecânismo não colisional conhecido por amortecimento de Landau, o qual é causado pela interação entre a onda eletrostática e partículas carregadas, íons no caso, e a taxa de amortecimento é maior próximo ao centro da coluna de plasma, onde o fator de segurança assume valores mais baixos. O equilíbrio MHD com rotação foi investigado em três regimes com relação às superfícies magnéticas: isotérmico, adiabático e isométrico. Foi observado que o gradiente de temperatura possui sentido oposto em relação à velocidade de rotação poloidal apenas no regime isométrico. Ao considerar equilíbrio com rotação e superfícies magnéticas isotérmicas e incluir fluxo de calor na equação da energia, observamos que ZF apresentam frequência não-nula, a qual é proporcional à velocidade de rotação poloidal e inversamente proporcional ao fator de segurança. Como direções futuras ressaltamos que é importante considerar efeitos eletromagnéticos, estudar automodos geodésicos e incluir o efeito de partículas aprisionadas para o desenvolvimento da física de ZF e GAM. Tal desenvolvimento beneficiará tanto a área de transporte em tokamaks como a área de diagnósticos, na qual a obtenção do perfil radial da temperatura de íons e do fator de segurança é um dos objetivos. Nesta área, um novo tipo de diagnóstico conhecido como espectroscopia em modos acústicos geodésicos está sendo desenvolvido baseado no estudo de automodos. / Due to the important role in drift wave turbulence and applications for plasma diagnostic purposes, the investigation of zonal flows (ZF) and associated geodesic acoustic modes (GAM) has arisen much attention in the plasma physics literature. In this thesis, first we consider equilibrium poloidal and toroidal rotation effects on these modes using the ideal MHD model, then we investigate diamagnetic effects on GAM using a two fluid model that includes parallel ion viscosity, and, in the final step, we include both Landau damping and diamagnetic effects on the study of GAM within the framework of the gyrokinetic model. By diamagnetic effects we mean the density and temperature radial gradients terms coming from the equilibrium Maxwellian distribution function. The effects caused by the coupling between the $m = \\pm1$ poloidal harmonics and the radial derivatives of equilibrium macroscopic quantities are responsible for an increase in the frequency value of the high frequency GAM and for an instability in the low frequency GAM. This instability, which is proportional to the electron drift frequency and the ratio between ion temperature and density gradients, are more likely to occur in radial positions where the safety factor is high. We observe that geodesic modes are slowly damped by a collisionlees mechanism known as Landau damping which is caused by the wave particle interaction between the eletrostatic potential and the íons. This damping is enhanced near the center of the plasma column, where the safety factor has lower values. Equilibrium MHD with plasma rotation were investigated in three regimes regarding the magnetic surfaces: isotherm, adiabatic and isometric. It is found that the temperature gradient has opposite directions compared to the poloidal rotation only for the isometric regime. By considering equilibrium rotation with isotherm magnetic surfaces and including heat flux we observed that ZF has a non-zero frequency which is proportional to the poloidal velocity and the inverse of the safety factor. For future directions we point out that electromagnetic effects, geodesic eigenmodes and trapped particles physics should be important for the development of the ZF and GAM physics, either in the area of anomalous transport caused by drift wave turbulence or for diagnostic purposes for obtaining the radial profile of the ion temperature and the safety factor. In this area, a new kind of diagnostic known as geodesic acoustic mode spectroscopy is being developing based on the study of eigenmodes.